Spring on track for Iowa trees, shrubs and flowers

As Spring officially arrives in Iowa, trees, shrubs and flowers are on track to bloom in full verdancy. Difficult and technical horticultural processes are at play as the state’s flora prepare for the season.

When snow melts and temperatures rise, light and moisture begin to stimulate vegetation in the state, according to Arthur Hill, a professor of horticulture at Iowa State University. This process is known as vernalization, whereby the plants become conditioned to the changing environment and flowers start to appear.

Hill explains that vernalization differs from germination, which is the emergence of a seedling from its seed. Rather, it is the process of a plant becoming adapted to seasonal environmental changes, such as the increasing amount of daylight and rising temperatures associated with springtime.

“The bud of a plant is already there and is just waiting for the right time to bloom,” Hill said. “Vernalization is the process that triggers the bud to open into a flower.”

The professor adds that when temperatures hover around freezing, the process of vernalization is inhibited, and plants may not bloom until temperatures become more favorable.

“The warmer temperatures and increased daylight of springtime enable the process of vernalization to progress,” Hill said.

He also noted that many plants require a period of cold in order to bloom, something that is known as “chilling” or “cold requirement.”

“Trees, shrubs and flowers need a certain number of hours of temperatures below zero in order to bloom,” Hill said. “If the cold requirement is not met, the plants may not be able to bloom.”

Hill emphasizes that it is important for Iowans to understand the technical processes at play in the seasonal transition, as it can help them plan their gardens accordingly.

“By understanding vernalization and the cold requirement of certain plants, people can ensure that their gardens will bloom in the spring,” Hill said.

He concluded, “We are on track for a beautiful spring in Iowa, and understanding the technical processes at play will help us make sure it will be a blooming success.”